Process of producing barium and strontium oxids.



' tity being readily determined by simple- UNITED STATES PATENT oFFioE.

- HARRY e; axnns, or TORONTO, ONTARIO, CANADA.

PROCESS No Drawing.

, Specification of Letters Patent.

or PRODUCING BABIUM AND s'rnon'rium OXIDS. I

To all whom it may concern:

Be it known that I, HARRY- G. AKERs,a citizen of Canada, and subject ofthe King of Great Britain, residing at Toronto, in the Province ofOntario and Dominion of Canada, have invented certain new and use fulImprovements in Processes of Producing Barium and Strontium Oxids; and Ido hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to the production of barium and strontium oxidsfrom their carbonates, and has for its purpose to provide a processwhich will accomplish these objects in peditious than those heretoforeproposed.

With these and other objects in view the invention consists in the novelsteps and combinations of steps constituting'my process, all as are morefully hereinafter disclosed and partic larly pointed out in the claims.

As is well known, barium or strontium carbonates which have beenemployed in the refining of molasses and therefore are more or lesscontaminated with lime, silica, organic substances, etc., are difiicultto fuse, and do not even (1., the exact temperature depending upon theamount and character of the impurities present. I have discovered,however, that these impure'carbonates can be readily melted atapproximately 1200 C. by adding small quantities of fluxes, such asfluorspar, soda ash, bor'ax, etc, the best quanand Well known tests, anddepending upon the character and quantity of the impur ities in thecarbonates. I have further dis covered that after the said carbonates,whether pure or not, have been melted they may be readily changed intooxids almost to completion at temperatures approximating to 1200 C.provided the partial pressure of the carbon dioxid liberated by thereaction be kept below that of the atmosphere and suflicient carbon bepresent. In some cases I have found a carbon lining for portions of thefurnace 'to yield good results, as it tends to assist in changing thecarbonates nto oxlds, and it is comparatlvely inexpensive to renew.

In carrying out my process the barium' a manner more efficient and ex- 1melt at 1200 C. or 1300? or strontium carbonates according to the natureof the impurities present may be.

w ith or without an admixed reducing agent, depending upon thesubsequent treatment said carbonates are to receiveffed into a suitablefurnace such, rotary cement kill with a flux may be conveniently in theform of a sludge, in which form it usually comes from the carbonat-ingtanks, and canbe dried in the stack end of the furnace by means of theexit-gases. This charge may then be melted in the body of the furnaceand admixed with a reducing agent as it is fed along, if no such agentbe already presout, and finally delivered into a suitable receptacle ina molten condition.

By so pro-portioning the carbon or other reducing agent as to compel alarge proportion of the carbon monoxid instead of carbon dioxid to begiven off, the exit gases will consist largely of nitrogen and carbonmonoxid, CO mixed with a less quantity of carbon dioxid, C0,, thepartialpressure of the latter will be low and the full value of saidgases may be employed to assist the heating and reduction of the charge.In other Words, adding a flux to these carbonates to allow them tofuseat approximately 1200 C. and mixing them with a carbonaceous substance,I accomplish the most desirable results of attaining a lower meltingpoint for said carbonates, whichallovs 's a better contact between thec'arbonate and the reduc- I Patented Oct. 13;, 1914. Application filedMay 8, 1913. Serial No. 766,410.

by the simple expedients of mg agent] and consequently allows thereduction to proceed readily at comparatively low temperatures. Further,the lowering of the said partial pressure greatly facilitates thereduction of the carbonates and enables me to accomplish the reductionto almost completion at temperatures approximating 1200 C. as abovestated, a result which would not be possible by the old methods, whileat the-same time the larger quantity of carbon'monoxid produced, enablesme to get a higher fuel value from the exit gases to aid in thereduction.

While the charge is in its molten condition it is sometimes desirable tofurther refine it by introducing a-reducing agent by means of a nozzledelivering compressed air vcharged with said agent in a, finely dividedcondition, or said agent may be blown through the molten material. Theselatter expedients'will be also useful when the I admixed therewith in anreducing agent has not been initially mixed with the charge as abovereferred to or was insufficient quantity,'o r has been burnt out by thegases produced in the previous stages of the process.

The advantages of my process will be aparent when one considers theeconomy due a to the/drying and'preheating of the crude carbonates whichare usually 1n the form of a sludge, the continuity'of the process, thecheapness of the equipment necessary for carrying it out, the lowertemperature and less .heat required, for the separation, and

andtherefore I donot wish to be limited to the above disclosure, exceptas may be required by the claims.

What I claim is p '1. The continuous process of roducing barium orstrontium' oxids from t eir crude carbonates which consists in mixingthe carbonate with a flux to lower its melting point; adding a reducingagent to the charge; meltingthe vcharge at a temperature ofapproximately 1200 .C.; igniting the evolved gases to heat the chargeand topreheat the incoming charge; and maintainlng a reducing atmospherein the reacting vessel conscribed.

2. The continuous process of producing taming said charge, substantiallyas debarium or strontium oxids from their crude carbonates whichconsists in mixing the carbonates with a flux to lower the meltingpoint; adding a reducing agent to the charge; melting the charge at atemperature of approximately 1200 C.; igniting the evolved gases to heatthe charge and to preheat the incoming-charge; maintaining a reducingatmosphere in the reacting vessel containing said charge; and causingthe gases produced by the combustion of the fuel employed'in heating thefurnace to dilute and thereby lower the partial pressure of any evolvedcarbon dioxid'from said charge, substantially as described.

3,. The continuous process of producing barium or strontium oxids fromtheir crude carbonates which consists in mixing the carbonates with aflux to'lower the melting point; adding a reducing agent to the charge;melting the charge at a temperature of approximately 1200 0.; refiningthe mass-by again adding afedu cing agent; causing the gases produced bythe combustion of the fuel employed in heating the furnace to dilute anyliberated carbon dioxid and thereby reduce its partial pressure;igniting-the evolved gases to heat the charge and to preheat the.incoming charge; and maintaining a reducing atmosphere in the reactingvessel containing said charge, sub- 'stantially as described.

i 4. The continuous process of producing barium or strontium oxids fromtheir crude carbonates in the form of a sludge which consists in mixingthe carbonates with a flux to lower the melting point; adding a reducingagent to the charge; melting the charge at, a temperature of aproximately 1290 C. 1n a carbon lined fiirnace; igniting the evolvedgases to heat the charge and to preheat the incoming charge; maintaininga reducing atmosphere in the reacting vessel containing sald charge; andcausing the gases produced by the combustion of the uel employed inheating the furnace to dilute and thereby lower the partial pressure ofan evolved carbon dioXid from said charge, su "stantially as described.

In testimony whereof I aflix my signature, in presence of two'witnesses.

HARRY GQAKERS. l/Vitnesses:

G. O. KINGSTON, J. JORDAN.

